Tc 9-524 fundamentals of machine tools

LATHE COMPONENTS
Engine lathes all have the same general functional parts,
even though the specific location or shape of a certain part
may differ from one manufacturer The bed is the foundation
of the working parts of the lathe to another (Figure 7-3).
Ways provide the means for holding the tailstock and
carriage, which slide along the ways, in alignment with the
permanently attached headstock
The headstock is located on the operator’s left end of the
lathe bed. It contains the main spindle and oil reservoir and
the gearing mechanism for obtaining various spindle speeds
and for transmitting power to the feeding and threading
mechanism. The headstock mechanism is driven by an
electric motor connected either to a belt or pulley system or to
a geared system. The main spindle is mounted on bearings in
the headstock and is hardened and specially ground to fit
different lathe holding devices. The spindle has a hole
through its entire length to accommodate long workplaces.
The hole in the nose of the spindle usually has a standard
Morse taper which varies with the size of the lathe. Centers,
collets, drill chucks, tapered shank drills and reamers may be
The main feature of its construction are the ways which are
inserted into the spindle. Chucks, drive plates, and faceplates
formed on its upper surface and run the full length of the bed.
may be screwed onto the spindle or clamped onto the spindle
nose.
7-3

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TC 9-524
The tailstock is located on the opposite end of the lathe
from the headstock. It supports one end of the work when
machining between centers, supports long pieces held in the
chuck, and holds various forms of cutting tools, such as drills,
reamers, and taps. The tailstock is mounted on the ways and is
designed to be clamped at any point along the ways. It has a
sliding spindle that is operated by a hand wheel and clamped
in position by means of a spindle clamp. The tailstock may be
adjusted laterally (toward or away from the operator) by
adjusting screws. It should be unclamped from the ways
before any lateral adjustments are made, as this will allow the
tailstock to be moved freely and prevent damage to the lateral
adjustment screws.
The carriage includes the apron, saddle, compound rest,
cross slide, tool post, and the cutting tool. It sits across the
lathe ways and in front of the lathe bed. The function of the
carriage is to carry and move the cutting tool. It can be moved
by hand or by power and can be clamped into position with a
locking nut. The saddle carries the cross slide and the
compound rest. The cross slide is mounted on the dovetail
ways on the top of the saddle and is moved back and forth at
90° to the axis of the lathe by the cross slide lead screw. The
lead screw can be hand or power activated. A feed reversing
lever, located on the carriage or headstock, can be used to
cause the carriage and the cross slide to reverse the direction
of travel. The compound rest is mounted on the cross slide and
can be swiveled and clamped at any angle in a horizontal
plane. The compound rest is used extensively in cutting steep
tapers and angles for lathe centers. The cutting tool and tool
holder are secured in the tool post which is mounted directly
to the compound rest. The apron contains the gears and feed
clutches which transmit motion from the feed rod or lead
screw to the carriage and cross slide.